A hydraulic cylinder is a mechanical actuator which may be used to give a linear force. The hydraulic cylinder may have varied applications and may be used in engineering vehicles and machines for example a demolition tool, which comprises of a jaw set that may be opened and closed by actuation of a hydraulic cylinder.
Hydraulic pressure from a pressurized fluid, such as oil, acts on the piston to perform linear work. Pressurized fluid may flow between a reservoir and the base side or rod side chambers of the hydraulic cylinder for cyclic operation thereof. Generally, flow of pressurized oil into the base side chamber may affect an extraction of the piston rod while flow of oil into the rod side chamber may affect retraction of the piston rod. Cycle time to extract or retract the piston rod may be dependent on multiple factors such as size of the cylinder. In certain engineering activities a reduction of the cycle time may be desired.
The cycle time of a hydraulic cylinder may be reduced by use of a speed valve or a regeneration valve.
U.S. Pat. No. 5,996,465 describes an oil-pressure cylinder in a crushing device connected to a crushing jaw to actuate the crushing jaw. Cylinder extension may cause the crushing jaw to close and crush an object. During a jaw closing stroke as the crushing jaw starts to close, to the point the crushing jaw comes into contact with the object, an acceleration (speed or regeneration valve) valve may make a continuous communication between a base-side port and a rod-side port in the cylinder. Oil from the rod-side port may be made to flow to the base-side port which may increase the movement-speed of the rod in the jaw closing stroke during the unloaded interval. When the crushing jaw comes into contact with the object, communication of the base-side port to the rod-side port is interrupted.
U.S. Pat. No. 7,540,231 describes a control valve device for the control of a dual-action consumer. A regeneration function allows the return side of the consumer to be connected with the admission side of the consumer. For the regeneration function, the connection of an additional pressure fluid line that forms the return side of the consumer with the reservoir can be blocked by a shutoff valve device located between the consumer and the control valve. The regeneration function may be overridden by an actuation of the shutoff valve device toward the open position as a function of the admission pressure at the admission side of the consumer. Under operating conditions wherein a high admission pressure is necessary to achieve high output power or increased performance, the regeneration function may be deactivated by the overriding of the regeneration function to ensure that the regeneration function is active only to achieve an increased speed of movement of the consumer.
Although the time to extract the piston rod may be increased, the aforementioned speed valves have a disadvantage in that the time to retract the piston rod is relatively long.
U.S. Pat. No. 5,542,180 describes a heavy duty shear comprising a fixed lower jaw and a movable upper jaw driven by a hydraulic cylinder. To overcome jams, the hydraulic cylinder is provided with an intensifier which pressurizes a portion of hydraulic fluid above the maximum pressure of the machine hydraulic system. The hydraulic fluid at a higher pressure is provided to the cylinder to facilitate opening of the jaws. The output pressure of the intensifier is selected to overcome the difference in the area at the rod side of the piston and area at the piston side of the piston.
The high pressure to open the jaw may be present only when a jam is to be cleared.
U.S. Pat. No. 5,415,076 describes fluid regeneration circuits which may be useful for filling expanding sides of a hydraulic cylinder with fluid being exhausted from the other side. A flow regeneration valve and a pressure boost valve may be used in combination with a meter-out valve for providing flow regeneration from the head end chamber to a rod end chamber when fluid pressure in the head end chamber is less than the pressure level of fluid in a passage as determined by a spring of the pressure boost valve. The pressure boost valve may be disposed within the passage and may be oriented to block fluid flow from the exhaust conduit to the inlet of the meter-out valve. The boost valve is biased to the closed position by the spring to block fluid flow from the inlet to the exhaust conduit until the fluid pressure in the inlet exceeds a predetermined level.
The pressure boost valve may be involved with control of fluid flowing to the tank and may not be involved in improving cycle time of the hydraulic cylinder.
The present disclosure is directed, at least in part, to improving or overcoming one or more aspects of the prior art system.